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Is Radioactive Dating Valid?
The long ages (billions of years) given by radioactive dating of rocks seems an impossibly long
time for some people. Since radioactive rocks have been observed for only a few decades, how
do you know you can trust these long halflifes and the long ages derived? Here are some points
to consider:
1.
The rate of decay should follow a simple exponential decline based on the simple theory
of probability in statistics. This same probability theory is used to figure the odds of
winning by gamblers.
2.
An exponential decay is seen for shortlived isotopes with halflives of only a few days.
3.
For the decades they have been observed, the longlived isotopes also follow an
exponential decay.
4.
The gamma ray frequencies and intensities produced by radioactive elements in
supernova remnants
change in the same predictable way as they do here on the Earth.
One wellstudied supernova remnant is SN1987A that is 169,000 light years away in a
satellite galaxy of the Milky Way. The predictions for the decay rates have turned out to
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This note was uploaded on 12/15/2011 for the course AST AST1002 taught by Professor Emilyhoward during the Fall '10 term at Broward College.
 Fall '10
 EmilyHoward
 Astronomy

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